Locking device



April 20, 1965 w. G. RICE ETAL 3,179,759

LOCKING DEVICE Filed Aug. 28, 1962 2 Sheets-Sheet l April 20, 1965 w. G. RICE ETAL 3,179,759

LOCKING DEVICE Filed Au 28, 1962 2 Shggis-Sheet 2 4a 23 "W 2 Z /2 EC 80/ led 8a United States Patent 3,17s,759 LocxrNG DEVICE William G, Rice and James J. Rusenko, Milwaukee, Wis,

assignors to (Iutler-Hamrner, Inc., Milwaukee, Wis, a corporation of Delaware Filed Aug. 28, 1962, Ser. No. 21,968 12 Claims. (Cl. 200-42) A more specific object of the invention is to provide an enclosed electric switch with improved means for locking the switch in any one of a plurality of operating positions and concurrently affording padlocking of its enclosure cover.

Another specific object of the inyention is to provide an enclosed electric switch with improved means for locking the switch in any one of a plurality of operating positions when its cover is open.

Another specific object of the invention is to provide an enclosed electric switch with improved means for locking its external operating handle in its oil position.

Another specific object of the invention is to provide an enclosed electric switch with improved means for locking its external operating handle in its on position.

Another specific object of the invention is to provide an enclosed electric switch with improved means whereby its operating handle cannot be locked when the switch is in one operating position but can be locked when the switch is in another operating position.

A further specific object of the invention is to provide an enclosed electric switch of the type having an exterior operating lever with improved convertible interlocking means which can readily be changed from a condition wherein neither the lever nor the enclosure cover can be locked when the lever is in one operating position to a condition wherein both the lever and the enclosure cover can be locked when the lever is in such operatingposition.

Other objects and advantages of the invention will hereinafter appear.

According. tothe invention, there is provided interlocking apparatus for an enclosed electric switch. The switch enclosure comprises a housing and a hinged cover or door for closing the front of the housing. The switch is mounted inside the housing and an operating handle is mounted exteriorly of the housing on a shaft which extends througha hole in the side wall of the housing for operating the switch therein. The interlocking apparatus comprises a cage secured to the side wall of the housing above the operating handle. A slot forming strap is secured to the edge of the door. A lock plate is slidably accommodated in the cage and is. biased by a spring into .its retracted position toward the rear of the housing. The lock plate has a catch projecting toward the operating handle and one .or more holes on its. extendable end for receiving padlocks. The base of the rotatable operating handle is provided with an arcuate flange. When the end of the lock plate is pushed through the slot in the door formed by the strap and a padlock attached thereto, the

'catch thereon interferes with the .flange on the handle to handle in its on" position.

3,179,?59 Patented Apr. 20, 1965 in certain applications such as where the switch is used for operating motors in continuous process lines such as steel rolling mills or the like, it becomes desirable to lock a series of switches in their on positions so that one motor cannot be deenergized while the other motors in the line are running. For this purpose, one end of the flange on the handle is provided with a tab which is scored to permit ready removal thereof to permit locking of the By removing this tab, the apparatus is converted readily from one type to another.

These and other objects and advantages of the invention and the manner of obtaining them will best be understood by reference to the following detailed description of an embodiment thereof taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a right side elevation view of switch enclosure showing the operating handle in its off position and the locking apparatus in its unlocked position;

FIG. 2 is a fragmentary enlarged view like that in FIG. 1 but showing the operating handle in its on position and the locking apparatus in its locked position;

FIG. 3 is a fragmentary enlarged rear elevation view of the operating handle and locking apparatus with the rear end of the lock plate broken away;

FIG. 4 is a view like that in FIG. 2 but showing the operating handle in its off position and the locking apparatus in its locked position;

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 4; and

FIG. 6 is an isometric view of the lock plate constituting a part of the locking apparatus of FIGS. 1 through 5.

Referring to FIG. 1, there is shown a switch enclosure comprising a housing 2 within which the switch is mounted and a hinged door or cover 4. The cover is preferably of the type which is hinged to the housing on its left side and is provided with a rearwardly extending flange 4a which overlaps the open edge of the housing when the cover is closed. The switch is provided with an operating handle 6 on the right side wallof the housing. This operating handle is connected to a rotatable shaft which extends into the housing through a hole in the right side of the housing and which hole is covered by the base 6a of the handle. Thus, rotation of the handle clockwise in FIG. 1 eitectsclosure of the switch and return of the handle counterclockwise etfects reopening of the switch. The details of the switch have not been shown as they are not necessary for a disclosure of the invention.

The locking device comprises means for latching the operating handle in a selected position and being elfective when so latched to receive at least one padlock to hold the latch in latching position and thereby to lock the cover closed or to hold the latch in latching position when the cover is open. This means comprises a lock plate 8 slidably mounted on the external right side wall of the housing directly above base 6a of the operating handle as shown in FIGS. 1 through 4. Lock plate 8 is provided with a raised catch 8:: depending at an angle toward the base of the operating handle for latching the operating handle in a selected position. Base 6a of the operating handle is provided with an arcuate flange 612 for engaging catch 8a to prevent rotation of the operating handle. Flange 6b is located such that its center point is approximately degrees clockwise from the operating handle and is given a length from its center point in the clockwise direction such that catch 8a almost abuts the clockwise end of this flange when the operating handle is in its counterclockwise olf position and lock plate 8 is slid in the left-hand direction to its operative or latching position as shown in FIGS. 1 and 4. Flange 6b is given a length from its center point in the counterclockwise direction such that lock plate 8 cannot be slid into its left-hand position when the operating handle is in its on position. In other words, when the operating handle is in its on position, the counterclockwise end portion of flange 6b is in the path of movement of catch 8a and blocks movement of the lock plate so that the latter cannot be slid far enough to the left to enable insertion of a shackle 10 of a padlock in one of the three holes 81; in the left-hand end portion of the lock plate.

However, means are provided for readily converting the apparatus from one wherein the operating handle cannot be latched in its on position to one wherein the operating handle can be latched in its on position. This means comprises a knockout type of readily removable tab 60 constituting the counterclockwise end portion of flange 6b. As shown in FIG. 1, tab 6c is partially cut or scored on its outer surface at 6d so that it can be broken off. When tab 60 has been removed as shown in FIGS. 2, 3 and 4, catch 8a clears flange 6b when the lock plate is slid into its extreme left-hand position. As a result,

the operating handle can now be latched in its on position as shown in FIG. 2. In FIG. 2, the operating handle has been moved from its extreme clockwise position slightly counterclockwise so that the counterclockwise end of flange 6b is in abutting engagement with catch 8a. While a single removable tab 60 has been shown in FIG. 1, the invention contemplates the provision of more than one tab on this end of flange 6b, different numbers of which can be arranged to be removed for different types of switches such as light duty, heavy duty and the like.

Lock plate 8 is provided with a cage 12 for guiding it for reciprocal sliding movement. Cage 12 is of generally channel shape with its upper and lower legs 12a bent outwardly and rigidly secured to the outer surface of the right wall of housing 2. The lower right-hand portion of this channel-shaped cage including most of the lower bent leg thereof has been cut out to allow catch 8a to project therefrom and to provide clearance for horizontal sliding movement of catch 8a and projection 8c. This cutout portion of the cage is provided with a vertical edge 12b for abutting engagement with projection 8c of the lock plate to limit the movement of the lock plate in the left-hand direction. Projection 80 may readily be formed by shearing and upsetting an outwardly projecting bead on the lock plate.

To prevent the locking device from interfering with rotation of the operating handle when the latter is not latched, the lock plate 8 is provided with a return spring 14. As shown in FIGS. and 6, the right-hand end portion of lock plate 8 has been formed to provide a cage for spring 14. For this purpose, on the left side of catch 8a lock plate 8 is provided with a bend 8d toward the wall of the housing and then toward the right along the wall of the housing and the extreme right-hand end of the lock plate is provided with a bend 3e away from the housing to form a stop for the right-hand end of spring 14. A narrow open slot 8 extends from bend 8e horizontally in the left-hand direction to accommodate spring 14. As shown in FIGS. 5 and 6, slot 8) is narrower than the diameter of spring 14 except at bend 80! where the slot is wider than the spring diameter to permit spring 14 to pass from one side of lock plate 8 to the other side. A tab 120 is formed at substantially the midportion of the channel on cage 12 and is bent inwardly into slot 8 to form a stop for the left-hand end of spring 14. In view of the aforementioned bends in the lock plate, a circular flat-topped bead 2a shown in FIGS. 4 and 5 is provided in the side wall of the housing to maintain the left-hand portion of the lock plate spaced from the housing wall and in the bottom of the channel in cage 12. This bead is required so that projection 8c engages edge 12b of the cage to limit the sliding movement of the lock plate.

A shallow U-shaped strap 16 with the ends of its legs bent outwardly is rigidly secured as by welding the bent ends to the right-hand flange 4a of cover 4. Strap 16 is in alinement with cage 12 and cooperates with the cover flange to form a vertical slot for receiving the left-hand end portion of lock plate 8 when the latter is slid into its latching position. Projection 8c is arranged on the lock plate so that it abuts edge 12!) when padlock holes 8b extend beyond strap 16.

As shown in FIG. 1, if lock plate 8 is slid in the lefthand direction and the shackle 10 of a padlock is inserted in one of the holes 812, the operating handle is locked in its off position as shown in FIG. 4. In this position, the cover 4 is also locked so that it cannot be opened unless the padlock is removed. When the lock plate is slid in the left-hand direction, spring 14 is compressed against tab by bend 8e. When the padlock is removed and the lock plate is released, spring 14 returns the lock plate in the right-hand direction into its normal or inoperative position. When tab 60 shown in FIG. 1 has been removed, the operating handle can also be locked in its on position as shown in FIGS. 2 and 3. A plurality of holes 8b are preferably provided so that when more than one attendant is making repairs, each one can disable the system until his repairs are completed. In this connection it will be apparent that the operating handle can be locked in either position when the cover is open. Shackle 10 of the padlock will bear against the edge of the housing to prevent the lock plate from sliding in the right-hand direction.

To assemble the device, cage 12 and strap 16 are first secured to the housing and cover, respectively, as by welding, riveting, bolting or the like. When cage 12 is made, tab 120 is not bent inwardly but rather is left in the plane of the channel. Spring 14 is then placed in the slot in lock plate 8 and the lock plate is slid in the left-hand direction according to FIG. 2 into cage 12. In the meantime a screwdriver is inserted into slot 12d immediately on the right side of tab 120 to serve as a stop for the lefthand end of spring 14 while tab 120 is bent inwardly into slot 8 in the lock plate. It will be apparent that tab 120 secures the parts together so that lock plate 8 cannot be removed from cage 12. As will be apparent from FIG.

5, if the lock plate is slid in the right-hand direction by spring 14, tab 120 will engage the left-hand end of slot 8 to limit the movement of the lock plate in that direction.

While the apparatus hereinbefore described is eitectively adapted to fulfill the objects stated, it is to be understood that we do not intend to confine our invention to the particular preferred embodiment of locking device disclosed, inasmuch as it is susceptible of various modifications without departing from the scope of the appended claims.

We claim:

1. In an enclosed electric switch having a housing provided with an open front and a cover for opening and closing the front of the housing, and a manually movable handle operable from the exterior of the enclosure for actuating the switch within the enclosure, the improvement comprising:

(a) means manually operable to latch the operating handle in one of its positions and being effective when so operated to receive means to hold the latching means in latching position and to lock the cover closed, said means comprising;

(b) a member having a catch thereon;

(c) means mounting said member on an exterior wall of the enclosure adjacent the operating handle for reciprocal movement independently of the cover when closed whereby said member has an inoperative position wherein said catch is clear of the operating handle and an operating handle and an operative position wherein said catch is in the path of movement of a portion of the operating handle to prevent actuation of the switch thereby;

(d) and means on said member effective when said member is moved into its operative position and being accessible in such position to receive said holding means to lock the cover closed.

2. The invention defined in claim 1, together with:

(a) cooperating means on said member and on said mounting means for limiting movement of said member in opposite directions.

3. The invention defined in claim 2, wherein said cooperating means comprises:

(a) a projection on said member for engaging an edge on said mounting means to limit movement of said member in its operative direction.

4. The invention defined in claim 1, together with:

(a) resilient means biasing said member into its inoperative position, said member being manually movable into its operative position against the force of said resilient means, and said resilient means being operative when said member is released to move the latter back into its inoperative position so that said catch does not interfere with movement of the operating handle.

5. The invention defined in claim 1, wherein said mounting means comprises:

(a) means for mounting said member for sliding movement between its operative and inoperative positions.

6. The invention defined in claim 5, wherein said cover is hinged to one wall of said housing and said operating handle is mounted to the opposite Wall of said housing, and said mounting means comprises:

(a) means for mounting said slidable member for sliding movement forwardly and in closely spaced relation to the wall of said housing adjacent said operating handle so that the forward end of said slidable member extends beyond the front edge of such wall;

(b) and said extended end of said slidable member having a hole therein for receiving the shackle of a padlock which abuts said front edge to lock said slidable member in its operative position when the cover is open.

7. In an enclosed electric switch having a housing provided with an open front and a cover for opening and closing the front of the housing, and a manually movable handle operable from the exterior of the enclosure for actuating the switch within the enclosure, the improvement comprising: I

(a) means manually operable to latch the operating handle in one of its positions and being effective when so operated to receive means to hold the latching means in latching position and to lock the cover closed, said means comprising:

(b) a member having a catch thereon;

(0) means mounting said member on an exterior wall of the enclosure adjacent the operating handle for reciprocal movement independently of the cover when closed whereby said member has an inoperative position wherein said catch is clear of the operating handle and an operative position wherein said catch is in the path of movement of a portion of the operating handle to prevent actuation of the switch thereby;

(d) means on said member effective when said member is moved into its operativeposition and being accessible in such position to receive said holding means to lock the cover closed;

(e) cooperating means on said member and on said mounting means for limiting movement of said mem her in opposite directions comprising;

(1) a slot in said member;

(g) and a tab on said mounting means bent into said slot to limit movement of said member in its inoperative direction and to prevent removal of said member from its mounting means.

8. In an enclosed electric switch having a housing provided with an open front and a cover for opening and closing the front of the housing, and manually movable handle operable from the exterior of the enclosure for 6 actuating the switch within the enclosure, the improvement comprising:

(a) means manually operable to latch the operating handle in one of its positions and being effective when so operated to receive means to hold the latching means in latching position and to lock the cover closed, said means comprising:

(b) a member having a catch thereon;

(c) means mounting said member on an exterior wall of the enclosure adjacent the operating handle for reciprocal movement independently of the cover when closed whereby said member has an inoperative position wherein said catch is clear of the operating handle and an operative position wherein said catch is in the path of movement of a portion of the operating handle to prevent actuation of the switch thereby;

(d) means on said member effective when said member is moved into its operative position and being accessible in such position to receive said holding means to lock the cover closed;

(e) said operating handle being of the rotary type and being provided with an arcuate flange at its base;

(1) and said catch abutting one end of said flange when said member is in its operative position to prevent rotation of said handle from its off position.

9. The invention defined in claim 8, wherein the other end of said flange is effective, when said operating handle is in its on position, to block movement of said catch thereby to prevent locking of said handle in its on position;

10. The invention defined in claim 9, wherein said other end of said flange is provided with a removable tab which, when removed to shorten said flange, allows movement of said catch past said other end of said flange thereby to afford locking of said operating handle in its on position.

11. In an enclosed electric switch having a housing provided with an open front and a cover for opening and closing the front of the housing, and a manually movable handle operable from the exterior of the enclosure for actuating the switch within the enclosure, the improvement comprising:

(a) means manually operable to latch the operating handle in one of its positions and being effective when so operated to receive means to hold the latching means in latching position and to lock the cover closed, said means comprising:

(b) a member having a catch thereon;

(0) means mounting said member on an exterior wall of the enclosure adjacent the operating handle for reciprocal movement independently of the cover when closed whereby said member has an inoperative position wherein said catch is clear of the operating handle and an operative position wherein said catch is in the path of movement of a portion of the op erating handle to prevent actuation of the switch thereby;

(d) means on said member effective when said member is moved into its operative position and being. accessible in such position to receive said holding means to lock the cover closed;

(e) said mounting means comprising means for mounting said member for sliding movement between its operative and inoperative positions;

(f) an elongated slot in said slidable member;

(g) a compression spring in said slot having one end abutting a portion of said member at one end of said slot;

(h) and a tab integral with said mounting means and being bent into said slot to abut the other end of said compression spring whereby said compression spring normally biases said slidable member into its inoperative position and said tab engages the other end of said slot to prevent removal of said slidable member from its mounting means.

12. In an enclosed electric switch having a housing provided with an open front and a cover for opening and closing the front of the housing, and a manually movable handle operable from the exterior of the enclosure for actuating the switch within the enclosure, the improvement comprising:

(a) means manually operable to latch the operating handle in one of its positions and being effective when so operated to receive means to hold the latching means in latching position and to lock the cover closed, said means comprising:

(b) a member having a catch thereon;

(c) means mounting said member on an exterior wall of the enclosure adjacent the operating handle for reciprocal movement independently of the cover when closed whereby said member has an inoperative position wherein said catch is clear of the operating handle and an operative position wherein said catch is in the path of movement of a portion of the operating handle to prevent actuation of the switch thereby;

(d) means on said member effective when said mem- Q My her is moved into its operative position and being accessible in such position to receive said holding means to lock the cover closed; (2) said cover being hinged to one wall of said housing 5 and said operating handle and said slidable member mounting means being mounted to the opposite wall of said housing; (f) a U-shaped strap secured to the side of said cover in alinement with said mounting means for receiving 10 an end portion of said slidable member therethrough;

(g) and said end portion of said slidable member having a hole therein for receiving the shackle of a padlock to lock the cover closed when said slidable member is in its operative position.

References Cited by the Examiner UNITED STATES PATENTS 1,473,001 11/23 White 20042 20 M. HENSON WOOD, 1a., Primary Examiner. 

1. IN AN ENCLOSED ELECTRIC SWITCH HAVING A HOUSING PROVIDED WITH AN OPEN FRONT AND A COVER FOR OPENING AND CLOSING THE FRONT OF THE HOUSING, AND A MANUALLY MOVABLE HANDLE OPERABLE FROM THE EXTERIOR OF THE ENCLOSURE FOR ACTUATING THE SWITCH WITHIN THE ENCLOSURE, THE IMPROVEMENT COMPRISING: (A) MEANS MANUALLY OPERABLE TO LATCH THE OPERATING HANDLE IN ONE OF ITS POSITIONS AND BEING EFFECTIVE WHEN SO OPERATED TO RECEIVE MEANS TO HOLD THE LATCHING MEANS IN LATCHING POSITION AND TO LOCK THE COVER CLOSED, SAID MEANS COMPRISING; (B) A MEMBER HAVING A CATCH THEREON; (C) MEANS MOUNTING SAID MEMBER ON AN EXTERIOR WALL OF THE ENCLOSURE ADJACENT THE OPERATING HANDLE FOR RECIPROCAL MOVEMENT INDEPENDENTLY OF THE COVER WHEN CLOSED WHEREBY SAID MEMBER HAS AN INOPERATIVE POSITION WHEREIN SAID CATCH IS CLEAR OF THE OPERATING HANDLE AND AN OPERATING HANDLE AND AN OPERATIVE POSITION WHEREIN SAID CATCH IS IN THE PATH OF MOVEMENT OF A PORTION OF THE OPERATING HANDLE TO PREVENT ACTUATION OF THE SWITCH THEREBY; (D) AND MEANS ON SAID MEMBER EFFECTIVE WHEN SAID MEMBER IS MOVED INTO ITS OPERATIVE POSITION AND BEING ACCESSIBLE IN SUCH POSITION TO RECEIVE SAID HOLDING MEANS TO LOCK THE COVER CLOSED. 